You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For consistency, answers should be in all lower cased letters.

Category: HEAVYWEIGHT CHAMPS 
Clue: This former heavyweight champ failed to regain his title against Gene Tunney in 1927's "Battle of the Long Count"
jack dempsey

Category: GO WITH THE FLOW 
Clue: The Tigris flows into this gulf
the persian gulf

Category: THE SPANISH-AMERICAN WAR 
Clue: A headline in Pulitzer's "The World" newspaper asked, was this ship's "Explosion Caused by Bomb or Torpedo?"

the maine