user: Question: How many times were the candidates Leven Powell (F) 63.8% Roger West (DR) 36.4%?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Virginia 1', 'Daniel Morgan', 'Federalist', 1797.0, 'Retired Federalist hold', 'Robert Page (F) 54.3% John Smith (DR) 45.7%']
SQL:

assistant: SELECT COUNT("First elected") FROM "Table" WHERE "Candidates" = 'Leven Powell (F) 63.8% Roger West (DR) 36.4%';