CREATE TABLE table_56421 ("Date" CLOB, "Opponent" CLOB, "Score" CLOB, "Loss" CLOB, "Attendance" CLOB, "Record" CLOB)

What is the date where the attendance was 31,220?
SELECT "Date" FROM table_56421 WHERE "Attendance" = '31,220'
SELECT "Date" FROM "table_56421" WHERE "Attendance" = '31,220'