CREATE TABLE table_72061 ("Date" CLOB, "Time" CLOB, "Competition" CLOB, "Opponent" CLOB, "Ground" CLOB, "Score" CLOB)

Who is the Opponent playing at 20:00 GMT at Camp Nou?
SELECT "Opponent" FROM table_72061 WHERE "Time" = '20:00 gmt' AND "Ground" = 'camp nou'
SELECT "Opponent" FROM "table_72061" WHERE "Ground" = 'camp nou' AND "Time" = '20:00 gmt'