Context: CREATE TABLE table_name_19 (round INTEGER, nationality VARCHAR, college_junior_club_team__league_ VARCHAR)
Question: Which Round has a Nationality of united states, and a College/Junior/Club Team (League) of breck school (ushs)?
Answer: SELECT MIN(round) FROM table_name_19 WHERE nationality = "united states" AND college_junior_club_team__league_ = "breck school (ushs)"