What is the average number of ties when goals against is less than 56 for Ottawa Hockey Club and the goals for is more than 47?
CREATE TABLE "final_standing" (
  "team" text,
  "games_played" real,
  "wins" real,
  "losses" real,
  "ties" real,
  "goals_for" real,
  "goals_against" real
);
SELECT AVG("ties") FROM "final_standing" WHERE "goals_against"<56 AND "team"='ottawa hockey club' AND "goals_for">47;