CREATE TABLE table_61899 ("Year" FLOAT, "Edition" CLOB, "Round" CLOB, "Date" CLOB, "Location" CLOB, "Surface" CLOB, "Against" CLOB, "Opponent ( s ) " CLOB, "Score" CLOB, "Result" CLOB)

Which Surface has an Opponent(s) of anna-lena gr nefeld tatjana malek?
SELECT "Surface" FROM table_61899 WHERE "Opponent(s)" = 'anna-lena grönefeld tatjana malek'
SELECT "Surface" FROM "table_61899" WHERE "Opponent(s)" = 'anna-lena grönefeld tatjana malek'