Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What was the engine class that was built on 1906-08?

### Inputs:
table_name: table, columns: ['Class', 'Firebox', 'Cylinder size', 'Valves', 'Valve gear', 'Number built', 'Years built']

### Response:
SELECT Class FROM table WHERE Years built = 1906-08