challenger
No, an incumbent is a person already holding the office and running for re-election.
"incumbent' is the word you want. I think.
The incumbent is the current office holder, the "challanger' is the person running against the incumbent
incumbent
Barack Obama is the incumbent US President, now campaigning for election to a second term.
The correct term for a current officeholder who is running for re-election is "incumbent."
If the incumbent barangay captain dies two days before election and he is also running as candidate as barangay captain for his last term, he is considered withdrawn from the election.
In mid-2012, Romney is seeking the nomination by the Republican party as its Presidential candidate in the November, 2012 election (likely running against incumbent president Barack Obama).
Barack Obama is the incumbent US President, now campaigning for election to a second term.
The only person currently (2012) running who is an African-American is the incumbent president, Barack Obama, who is running for re-election.
The incumbent is the current holder of a political office. This term is usually used in reference to elections, in which races can often be defined as being between an incumbent and non-incumbent
Ronald Reagan won the 1980 presidential election defeating incumbent President Jimmy Carter. Incumbent President Ronald Reagan won reelection in the 1984 presidential election defeating Walter Mondale.