user: Question: How many directors were there for the production code 1ARK08?
Columns: ['No.', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'Viewers (in millions)']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '"Pilot"', 'Todd Holland', 'Greg Bratman & Tommy Dewey', 'March11,2010 (CAN) March14,2010 (US)', '1ARK79', '4.514']
SQL:

assistant: SELECT COUNT("Directed by") FROM "Table" WHERE "Production code" = '1ARK08';