Which men's singles had a women's doubles team of irena ferencová / yweta trminková?
CREATE TABLE "junior_champions" (
  "year" real,
  "men_s_singles" text,
  "women_s_singles" text,
  "men_s_doubles" text,
  "women_s_doubles" text,
  "mixed_doubles" text
);
SELECT "men_s_singles" FROM "junior_champions" WHERE "women_s_doubles"='irena ferencová / yweta trminková';