GOP state Sen. Neil Riser and Republican businessman Vance McAllister advanced to a runoff Saturday night in a special election in Louisiana’s 5th District, rising above a crowded field of 14 candidates from all over the political spectrum.

Riser received 33 percent, with 88 percent of precincts reporting, according to The Associated Press. McAllister captured the second spot in the runoff, garnering 18 percent.

This is the contest to replace former Rep. Rodney Alexander, who resigned in September to take a job in Gov. Bobby Jindal’s cabinet.

The runoff will showcase a contrast between Riser, a politician who has the support of GOP leaders such as Majorty Leader Eric Cantor of Virginia, and McAllister, a businessman who has depicted himself as an outsider.

Riser was widely expected to take the first-place runoff spot in the open primary. But the race for second place was wide open.

In Louisiana, all candidates run in one primary ballot, regardless of party. If a candidate receives 50 percent of the vote, he or she wins the election outright. But if no candidate surpasses that threshold, the top two vote recipients advance to a runoff that determines the winner of the seat, regardless of party affiliation.

Because no candidate passed that threshold in this contest, Riser and McAllister will face off in a Nov. 16 runoff that will determine the next member from this deeply conservative district in the northeast corner of the state.

McAllister defeated Monroe Mayor Jamie Mayo, a Democrat from one of the district’s largest cities, and former Rep. Clyde Holloway, who was the fifth-place finisher. Holloway has now lost his fourth comeback bid since he left Congress in 1993.

Louisiana’s 5th District is rated a Safe Republican contest by Rothenberg Political Report/Roll Call.