CREATE TABLE table_27157 ("Year" FLOAT, "Mens singles" CLOB, "Womens singles" CLOB, "Mens doubles" CLOB, "Womens doubles" CLOB, "Mixed doubles" CLOB)

Who played Mixed Doubles in 1991?
SELECT "Mixed doubles" FROM table_27157 WHERE "Year" = '1991'
SELECT "Mixed doubles" FROM "table_27157" WHERE "Year" = '1991'