 Demmas worked much of his career as the umpire on the crew of a fellow AFL official, referee Ben Dreith.During the fourth quarter of Super Bowl XIII, Dallas Cowboys safety Charlie Waters collided with Demmas as he was moving into position to tackle Pittsburgh Steelers running back Franco Harris.Harris scored a touchdown on the play, giving the Steelers a 28–17 lead, and Pittsburgh went on to win the game, 35–31.