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

### Instruction:
What is the primary conference with a IHSAA Football Class of A, at South Decatur school?

### Inputs:
table_name: table, columns: ['School', 'Location', 'Mascot', 'Enrollment', 'IHSAA Football Class', 'Primary Conference', 'County']

### Response:
SELECT Primary Conference FROM table WHERE IHSAA Football Class = a AND School = south decatur