Table: mitteldeutscher bc
Question: What is the ratio of the mitteldeutscher bc's promotions and relegations over the last 15 seasons?
Step 1 (Operation, Filter): season
Step 2 (Reasoning, Aggregating): COUNT, promotions
Step 3 (Reasoning, Aggregating): COUNT, relegations
Step 4 (Reasoning, Arithmetic): /, ratio
Answer: 1:2