(CNN) - Voters in Arizona's 8th Congressional District cast their ballots Tuesday in the primary ahead of the special election to replace former Democratic Rep. Gabrielle Giffords.
The congresswoman resigned from her seat in January to focus on her recovery from the Tucson shooting that killed six and wounded 13 others, including Giffords.
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Ron Barber, longtime Giffords' aide who was wounded in the shooting, ran unopposed on the Democratic ticket and won with 98% of the vote, according to unofficial results from the Arizona Secretary of State's office.
On the Republican side, four candidates campaigned for the seat, with Jesse Kelly emerging as the winner with 36%.
A construction manager and Iraq war veteran, Kelly nearly defeated Giffords when he last ran for Congress in 2010, falling only two points behind in the final count with 46% to Giffords' 48%.
The two candidates, Barber and Kelly, will face off in the special election on June 12.
In terms of fundraising, Barber has far outpaced his Republican counterpart, taking in nearly $540,000, while Kelly has received more than $220,000 in contributions, according to Federal Election Commission reports.
If Kelly manages a victory, however, he will change the makeup of Arizona's House delegation to six Republicans and two Democrats.
While the 8th district has been represented by Giffords, a moderate Democrat, for the last three terms, it voted for George W. Bush in 2000 and 2004, and for John McCain in 2008.
The Grand Canyon State has added a new 9th Congressional District due to population gains in the 2010 census. Campaigns are already underway for the seat, which will be decided in the House 2012 election cycle later this year.