CREATE TABLE table_11713 ("Date" CLOB, "Opponent" CLOB, "Score" CLOB, "Loss" CLOB, "Attendance" FLOAT, "Record" CLOB)

Who was the opponent on September 17?
SELECT "Opponent" FROM table_11713 WHERE "Date" = 'september 17'
SELECT "Opponent" FROM "table_11713" WHERE "Date" = 'september 17'