CREATE TABLE table_name_41 (ties INTEGER, goals_for VARCHAR(255), goals_against VARCHAR(255), team VARCHAR(255))
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?
    
SQL: SELECT AVG(ties) FROM table_name_41 WHERE goals_against < 56 AND team = "ottawa hockey club" AND goals_for > 47