user: Question: What model has a number built smaller than 6.526, and the Chassis code W109.015?
Columns: ['Model', 'Chassis code', 'Production time', 'Number built', 'Engine']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['300SEL', 'W109.015', '09/65 - 12/67', 2.369, '3.0L M189 I6']
SQL:

assistant: SELECT "Model" FROM "Table" WHERE "Number built" < 6.526 AND "Chassis code" = 'W109.015';