(CNN) - The Conservative Party candidate in the special election for New York's 23rd congressional district has a 5-point edge over the Democrat in the race, according to a new poll.
But the Siena Research Institute survey, conducted the day after the Republican in the race suspended her campaign, suggests that roughly one out of five voters in the district remain undecided just hours before Election Day.
The race has captured national attention because of a split among Republicans, which could allow a Democrat to win the district for the first time in over a century.
The poll indicates that 41 percent of likely voters support Conservative candidate Doug Hoffman, with 36 percent backing Democrat Bill Owens, and 6 percent supporting Republican nominee Dede Scozzafava, who suspended her campaign on Saturday. Scozzafava's name remains on the ballot.
Eighteen percent of likely voters are undecided, double the amount from a Siena survey released Saturday, hours before Scozzafava dropped out of the race. Owens was at 36 percent in that poll, with Hoffman at 35 percent and Scozzafava grabbing one in five voters.
Scozzafava suspended her campaign after a flood of support and contributions by some top conservative names and organizations for Hoffman. Over the past few weeks, the fiscally conservative Club for Growth and the Hoffman campaign have both hit the air with TV spots that paint the third-party candidate as the race's true conservative.
"Hoffman continues to demonstrate momentum, picking up 6 points since Scozzafava pulled out," says Siena pollster Steven Greenberg. "It appears, however, that the majority of Scozzafava's supporters have gone to neither Hoffman nor Owens, but rather into the undecided column, which has doubled since Scozzafava ended her candidacy."
The survey suggests that Hoffman has increased his lead among Republicans, while Owens maintains his advantage among Democrats and has captured a slight lead among independents from Hoffman.
"Owens kept his lead in the northeastern counties steady, while Hoffman extended his lead in the southern counties, and the two are dead even in the northwestern counties, the area in which Scozzafava previously led," says Greenberg
"With nearly one in five voters undecided the day before Election Day and voters still trying to comprehend the dramatic withdrawal of Scozzafava, and her subsequent endorsement of Owens, this is still a wide open race," adds Greenberg.
The seat opened up after nine-term Republican Rep. John McHugh stepped down after being confirmed as Secretary of the Army. The largely rural district spans 11 counties in northern New York.
Republicans have represented this area of the state since 1872. McHugh never won less than 60 percent of the vote in his nine election victories, but Barack Obama did edge out John McCain in the district in last year's presidential election.
Scozzafava won the nomination in a vote taken by the 11 GOP county chairs in the district, rather than through a traditional primary election. The local Republican leaders picked the state assemblywoman, who was also backed by the National Republican Congressional Committee, because they felt her moderate views would appeal to centrist Republicans, independents, and even some Democrats.
The move sparked a revolt among many conservatives, who were angry with what they call her liberal views on same-sex marriage and abortion. They are backing Hoffman, an accountant, who is running on the Conservative Party line.
The Siena College Research Institute poll was conducted Sunday November 1, with 606 likely voters questioned by telephone. The survey's sampling error is plus or minus 4 percentage points.
Follow Paul Steinhauser on Twitter: @psteinhausercnn