The GOP held on to a Mississippi congressional seat in a special-election runoff Tuesday in which a Republican district attorney handily defeated a fellow attorney and Democratic political consultant who was seeking his first public office.

Trent Kelly will serve most of a two-year term started by Republican Rep. Alan Nunnelee, who was first elected in 2010 and won a third term in 2014 as he struggled with health problems. Nunnelee was 56 when he died of brain cancer in February.

"We ran a very simple campaign, and it was about who I am and why I want to be a congressman," Kelly told supporters at his victory party Tuesday night in Tupelo. "God is first in my life."

Kelly, 49, of Saltillo, is district attorney for seven counties, about one-third of north Mississippi's 1st Congressional District. He was supported by Republicans, including Gov. Phil Bryant and Nunnelee's widow, Tori, and was the favored candidate in a district that has been controlled by Republicans for most of the past 20 years.

If the Democrat, 34-year-old Walter Zinn of Pontotoc, had pulled off an upset, he would have become only the third African-American congressman in Mississippi since Reconstruction.

With 100 percent of precincts reporting, Kelly had 70 percent of the vote and Zinn had 30 percent.

Now, the only vacant seat in the 435-member U.S. House is in Illinois, where Republican Rep. Aaron Schock resigned in March amid questions about his spending. The primary in central Illinois' 18th District is July 7, and the special election is Sept. 10. With Kelly joining the House, Republicans will hold 246 seats and Democrats will hold 188.

Kelly is a military veteran who did two tours of combat duty in Iraq. He campaigned on keeping a strong national defense, protecting veterans' benefits, cutting spending and limiting federal regulations on businesses.

In an election-night interview with the Northeast Mississippi Daily Journal, Tori Nunnelee praised Kelly's military service and called him a "humble man."

"I think Congressman Kelly will represent us well," she said.

The district includes all of or part of 22 counties, stretching from the Tennessee line down to Winston County in central Mississippi. Before the seat became controlled by Republicans, it was held for 53 years by Democrat Jamie Whitten, who worked his way up to the chairmanship of the House Appropriations Committee and brought millions of federal dollars to one of the poorest states in the nation.

Zinn and Kelly advanced to the runoff from a field of 13 candidates in the first round of voting May 12. Kelly outspent Zinn, who received little backing from national Democratic groups.

Turnout typically decreases between an election and a runoff, but it increased for the runoff in this race: 88,364 people voted May 12, and more than 98,200 voted Tuesday.