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

### Instruction:
What team was promoted in the Serbian League East in the same season when Kolubara was promoted in the Serbian League Belgrade?

### Inputs:
table_name: table, columns: ['Season', 'Serbian League Belgrade', 'Serbian League East', 'Serbian League Vojvodina', 'Serbian League West']

### Response:
SELECT Serbian League East FROM table WHERE Serbian League Belgrade = Kolubara