Who won the mixed doubles in 1957 when judy devlin won the women's singles?
CREATE TABLE "canadian_national_championships_and_cana" (
  "year" real,
  "men_s_singles" text,
  "women_s_singles" text,
  "men_s_doubles" text,
  "women_s_doubles" text,
  "mixed_doubles" text
);
SELECT "mixed_doubles" FROM "canadian_national_championships_and_cana" WHERE "women_s_singles"='judy devlin' AND "year"=1957;