LOS ANGELES — LeBron James picked a winner in the NBA All-Star Game. James scored 29 points and hit the go-ahead layup with 34.5 seconds to play, winning his third All-Star Game MVP award while his hand-picked team rallied to win an uncommonly entertaining showcase, beating Team Stephen 148-145 Sunday night. For the first time in the 67 editions of the All-Star Game, the league abandoned the traditional East-West format used since 1951 and allowed team captains James and Stephen Curry to choose their own rosters. That twist turned a sometimes staid event into the world’s richest pickup game, and the intrigue was reflected on the Staples Center court, where a real basketball game broke out. LeBron’s team even won an All-Star game with defense: On the final possession, James and Kevin Durant blanketed Curry, preventing the 3-point-shooting superstar from getting off a potential tying shot. “I think myself and Stephen took it upon ourselves when we took on this format that we had to change the way this game was played,” said James, who also had 10 rebounds and eight assists. Both teams played defense for long stretches and contested many shots, with LeBron’s group even picking up full-court late in the first half.