The billionaire mall magnate Rick Caruso is heading for a November run-off against Democratic congresswoman Karen Bass for the job of L.A. mayor. With 16 percent of the vote counted from Monday’s primary, Caruso was leading Bass by 41.4 to 37.2 percent, both short of the 50 percent mark needed to claim outright win. “This is a great night because so many people have gone to the voting booth and they sent a message: We are not helpless in the face of our problems,” Caruso told supporters at his Grove shopping mall in Fairfax. The 63-year-old property developer has long been a Republican but changed his affiliation to Democrat when launching his mayoral campaign. Bass, who chairs the Congressional Black Caucus, addressed her supporters on the roof of the W Hotel in Hollywood. “We are in a fight for the soul of our city and we are going to win,” she said.