CREATE TABLE table_203_581 (id NUMBER, "club" CLOB, "chinese" CLOB, "city" CLOB, "home stadium" CLOB, "capacity" NUMBER, "average attendance" NUMBER)

what is the average attendance for all stadiums ?
SELECT "average attendance" FROM table_203_581 WHERE agg = 1
SELECT "average attendance" FROM "table_203_581" WHERE "agg" = 1