Complex sentence: The city's teams have endured an unprecedented combined 156-season championship drought, having not won a title since 1964, when the Browns the NFL Championship Game, two seasons prior to the first Super Bowl.
Split into simpler sentences: The city's teams have endured an unprecedented combined 156-season championship drought, having not won a title since the Browns won in 1964. Although the Browns won that game, it occurred two seasons prior to the first Super Bowl.