CREATE TABLE table_6654 ("Date" TEXT, "City" TEXT, "Opponent" TEXT, "Results\\u00b9" TEXT, "Type of game" TEXT)

Who was the opponent in Belgrade and had a result of 5:2?
SELECT "Opponent" FROM table_6654 WHERE "City" = 'belgrade' AND "Results\u00b9" = '5:2'
SELECT "Opponent" FROM "table_6654" WHERE "City" = 'belgrade' AND "Results\u00b9" = '5:2'