user: Question: If the chief judge is Jeffrey L. Viken, what is the region?
Columns: ['Region', 'Citation', 'Court of Appeals', 'Established', 'Judges', 'Meeting places', 'Chief judge']
Types: ['text', 'text', 'text', 'real', 'real', 'real', 'text']
Sample row: ['Northern District of Alabama', 'N.D. Ala.', '11th', 1820.0, 8.0, 8.0, 'Sharon Lovelace Blackburn']
SQL:

assistant: SELECT "Region" FROM "Table" WHERE "Chief judge" = 'Jeffrey L. Viken';