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David Vitter's seat was the U.S. Senate seat that Joseph Cao ran for in 2016. Cao, a Republican, challenged incumbent Democrat Vitter in the general election. Vitter had been appointed to the seat in 2004 and won re-election in 2006. In the 2016 election, Vitter was defeated by Cao, who became the first Vietnamese-American elected to the U.S. Senate.