user: Question: Which position has a Nationality of United States, and a Player of Roger Powell?
Columns: ['Player', 'Nationality', 'Position', 'Years for Jazz', 'School/Club Team']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Scott Padgett', 'United States', 'Forward', '1999-2003', 'Kentucky']
SQL:

assistant: SELECT "Position" FROM "Table" WHERE "Nationality" = 'United States' AND "Player" = 'Roger Powell';