Table: pittsburgh_riverhounds_stats
Columns: year
division
league
regular_season
playoffs
u_s_open_cup
avg_attendance

Question: Which regular season was 2013 in?
SQL: SELECT "regular_season" FROM pittsburgh_riverhounds_stats WHERE "year" = 2013

Question: What year did the team make conference semifinals?
SQL: SELECT COUNT("year") FROM pittsburgh_riverhounds_stats WHERE "playoffs" = 'conference semifinals'