CREATE TABLE table_68459 ("Outcome" CLOB, "Date" CLOB, "Surface" CLOB, "Opponent" CLOB, "Score" CLOB)

What was the surface of the match against bethanie mattek-sands?
SELECT "Surface" FROM table_68459 WHERE "Opponent" = 'bethanie mattek-sands'
SELECT "Surface" FROM "table_68459" WHERE "Opponent" = 'bethanie mattek-sands'