CREATE TABLE table_name_56 (opposition VARCHAR2, stadium VARCHAR2, attendance VARCHAR2)

Who's the opposition at westpac stadium when the attendance is 31,853?
SELECT opposition FROM table_name_56 WHERE stadium = "westpac stadium" AND attendance = "31,853"
SELECT "opposition" FROM "table_name_56" WHERE "31,853" = "attendance" AND "stadium" = "westpac stadium"