Haney has a sizeable lead over Campos receiving about 63 percent of the vote.
The winner will fill David Chiu's District 17 seat, who resigned after being named city attorney by Mayor London Breed.
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Haney took to Twitter Tuesday night and declared victory.
Mayor Breed will now select Haney's replacement on the board of supervisors.
The runoff was necessary because neither candidate got 50 percent of the vote in February's special election.
Bay City News contributed to this story.