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

### Instruction:
Which conference joined in 1954 with a beavers mascot?

### Inputs:
table_name: table, columns: ['School (IHSAA ID#)', 'Location', 'Mascot', '# / County', 'Year Joined', 'Year Left', 'Conference Joined']

### Response:
SELECT Conference Joined FROM table WHERE Year Joined = 1954 AND Mascot = beavers