CREATE TABLE table_17519 ("Year" FLOAT, "Mens singles" TEXT, "Womens singles" TEXT, "Mens doubles" TEXT, "Womens doubles" TEXT, "Mixed doubles" TEXT)

Who is themens doubles when the mens singles is flemming delfs?
SELECT "Mens doubles" FROM table_17519 WHERE "Mens singles" = 'Flemming Delfs'
SELECT "Mens doubles" FROM "table_17519" WHERE "Mens singles" = 'Flemming Delfs'