CREATE TABLE table_36304 ("Tournament" TEXT, "1988" TEXT, "1989" TEXT, "1990" TEXT, "1991" TEXT, "1992" TEXT, "1993" TEXT, "1994" TEXT, "1995" TEXT, "1996" TEXT, "1997" TEXT, "1998" TEXT)

Which 1991 has an A 1993 ?
SELECT "1991" FROM table_36304 WHERE "1993" = 'a'
SELECT "1991" FROM "table_36304" WHERE "1993" = 'a'