user: Question: Name the party with first elected more than 1999 and position of Supervisor for John Foust
Columns: ['Position', 'Name', 'Party', 'First elected', 'District']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Chairman', 'Sharon Bulova', 'Democratic Party', 2009.0, 'At-Large']
SQL:

assistant: SELECT "Party" FROM "Table" WHERE "First elected" > 1999.0 AND "Position" = 'Supervisor' AND "Name" = 'John Foust';