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

### Instruction:
When was the first elected when the party was republican and the candidate were robert h. michel (r) 66.1% rosa lee fox (d) 33.9%?

### Inputs:
table_name: table, columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']

### Response:
SELECT MIN First elected FROM table WHERE Party = Republican AND Candidates = Robert H. Michel (R) 66.1% Rosa Lee Fox (D) 33.9%