Complex sentence: The 1949--50 NBA season was the inaugural season of the National Basketball Association, which was created in 1949 by merger of the 3-year-old BAA and 12-year-old NBL.
Split into simpler sentences: The 1949--50 NBA season was the inaugural season of the National Basketball Association. The league was created in 1949 by merger of the 3-year-old BAA and 12-year-old NBL.