CREATE TABLE table_15135 ("Outcome" CLOB, "Date" CLOB, "Tournament" CLOB, "Surface" CLOB, "Partner" CLOB, "Opponents" CLOB, "Score" CLOB)

On which surface was the score w/o?
SELECT "Surface" FROM table_15135 WHERE "Score" = 'w/o'
SELECT "Surface" FROM "table_15135" WHERE "Score" = 'w/o'