How old were Mitchell & Jessica when they danced the Cha-Cha-Cha?
CREATE TABLE "junior_ballroom_dancing_competition" (
  "date" text,
  "round" real,
  "pair" text,
  "ages" text,
  "dance" text,
  "song" text
);
SELECT "ages" FROM "junior_ballroom_dancing_competition" WHERE "dance"='cha-cha-cha' AND "pair"='mitchell & jessica';