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

which stadium only has a capacity of 20,000 ?
SELECT "home stadium" FROM table_203_581 WHERE "capacity" = 20000
SELECT "home stadium" FROM "table_203_581" WHERE "capacity" = 20000