Complex sentence: The 2011--12 Parma season ran from August 2011 to May 2012, the club's 21st season in Serie A and their third consecutive season in that division, having finished in 12th position the previous season.
Split into simpler sentences: The 2011--12 season of Parma F.C. ran from August 2011 to May 2012. It was Parma's 21st season in Serie A and their 3rd consecutive season in that division, having finished in twelfth position the previous season.