CREATE TABLE table_14640 ("Year" CLOB, "Men's singles" CLOB, "Women's singles" CLOB, "Men's doubles" CLOB, "Women's doubles" CLOB, "Mixed doubles" CLOB)

When Marja Ridder won the Women's singles who won the Men's singles?
SELECT "Men's singles" FROM table_14640 WHERE "Women's singles" = 'marja ridder'
SELECT "Men's singles" FROM "table_14640" WHERE "Women's singles" = 'marja ridder'