SCHEMA:
CREATE TABLE table_name_18 (college_junior_club_team__league_ VARCHAR, player VARCHAR, round VARCHAR, position VARCHAR, nationality VARCHAR)
USER:
What is College/Junior/Club Team (League), when Position is "Defence", when Nationality is "Canada", when Round is less than 5, and when Player is "Josiah Didier"?

QUERY:
SELECT college_junior_club_team__league_ FROM table_name_18 WHERE position = "defence" AND nationality = "canada" AND round < 5 AND player = "josiah didier"