CREATE TABLE table_17521 ("Year" FLOAT, "Mens singles" TEXT, "Womens singles" TEXT, "Mens doubles" TEXT, "Womens doubles" TEXT, "Mixed doubles" TEXT)

Who was the mens doubles when womens singles is mette s rensen?
SELECT "Mens doubles" FROM table_17521 WHERE "Womens singles" = 'Mette Sørensen'
SELECT "Mens doubles" FROM "table_17521" WHERE "Womens singles" = 'Mette Sørensen'