What College/junior/club had a player of United States nationality drafted by the Toronto Maple Leafs?
CREATE TABLE "round_seven" (
  "pick_num" text,
  "player" text,
  "position" text,
  "nationality" text,
  "nhl_team" text,
  "college_junior_club_team" text
);
SELECT "college_junior_club_team" FROM "round_seven" WHERE "nhl_team"='toronto maple leafs' AND "nationality"='united states';