Updated 11/13/2013 at 5:58 p.m. ET
(CNN) - Democratic state Sen. Mark Herring was 164 votes ahead of Republican state Sen. Mark Obenshain on Wednesday afternoon in an unofficial tally in the race for Virginia Attorney General.
Should Herring become the certified winner, he would be the third of three Democrats to win top-of-the-ballot seats. Former Democratic National Committee Chairman Terry McAuliffe won the gubernatorial race and Democrat Ralph Northam was elected lieutenant governor.
Tuesday was the deadline for all state localities to finish their vote canvasses and the state board of elections certifies the results on November 25.
Changes in the vote count are normal during the post-election period, according to the commonwealth's board of elections. And with the margin being less than 1%, the losing candidate is allowed to petition the board for a recount after the November 25 certification date.
As of the latest count, Herring leads Obenshain 1,103,777-1,103,613, a difference of 0.01%.
The race is close enough that Obenshain announced Wednesday he would form a transition team, despite his opponent's slight lead.
"I don't know who's going to move into the Attorney General's office in January and despite what Mark Herring says, he doesn't know either," Obenshain said, although he would not commit to launching a recall petition, preferring to "wait and see."
"With historically narrow margins and with the vote total yet to be ascertained, the responsible thing to do at this point is to prepare for a transition," Obenshain said, noting that in the nearly-as-close 2005 race for Attorney General, both candidates (one being now-Gov. Bob McDonnell) formed transition teams.
The transition team is necessary to be "ready to take up the important work of the attorney general's office," Obenshain said.
Herring spokesman Kevin O'Holleran said the campaign was confident the final results would be a win. Asked if Herring would file an appeal if Obenshain pulls ahead in the final count, O'Holleran said it was "too early" to consider that.
State election law does not allow candidates to challenge absentee and provisional ballots that were ruled invalid, or the eligibility of voters. It does, however, allow candidates to challenge whether or not standard ballots were tallied correctly.
Democrats haven't swept all three statewide offices in Virginia since 1989, when L. Douglas Wilder became the nation's first African-American governor. It could happen again this year.
The state, which has become a crucial swing state in presidential elections, also has Democrats as its two U.S. senators.
– CNN's Ashley Killough, Peter Hamby, Bryan Koenig and Dan Merica contributed to this report.