CREATE TABLE table_67328 ("Outcome" CLOB, "Tournament" CLOB, "Surface" CLOB, "Partner" CLOB, "Opponents" CLOB, "Score" CLOB)

What surface was the citt di caltanissetta played on?
SELECT "Surface" FROM table_67328 WHERE "Tournament" = 'città di caltanissetta'
SELECT "Surface" FROM "table_67328" WHERE "Tournament" = 'città di caltanissetta'