CREATE TABLE table_69055 ("Year" TEXT, "Men's singles" TEXT, "Women's singles" TEXT, "Men's doubles" TEXT, "Women's doubles" TEXT, "Mixed doubles" TEXT)

Who won the mixed doubles in the years that the men's doubles has no competition?
SELECT "Mixed doubles" FROM table_69055 WHERE "Men's doubles" = 'no competition'
SELECT "Mixed doubles" FROM "table_69055" WHERE "Men's doubles" = 'no competition'