Louisiana will have to wait another month to elect its next U.S. senator.

Democrat Foster Campbell and Republican John Kennedy are set to square off on Dec. 10, an automatic runoff triggered when no candidate earned more than 50 percent of the vote in Tuesday’s election.

Kennedy led Campbell 25-to-17 percent with 99 percent of precincts reporting early Wednesday morning. Republican Charles Boustany (15.4 percent), Democrat Caroline Fayard (12.5 percent) and Republican John Fleming (10.5 percent) were the only other candidates in a crowded field to win more than 10 percent of the vote.

Kennedy, the Louisiana state treasurer, and Campbell, the public service commissioner, are vying to replace retiring Republican Sen. David Vitter.

White supremacist David Duke was also running but had not polled in the top-tier in the field of two dozen candidates. Duke had captured just 3 percent of the vote as of Wednesday morning.