user: ### NOW ANSWER:
Question: Which Round has a Nationality of United States, and a Player of Jimmy Hayes?
Columns: ['Round', 'Pick', 'Player', 'Position', 'Nationality', 'Club Team']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '5', 'Luke Schenn', '(D)', 'Canada', 'Kelowna Rockets ( WHL )']
SQL:

assistant: SELECT MAX("Round") FROM "Table" WHERE "Nationality" = 'United States' AND "Player" = 'Jimmy Hayes';