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

### Instruction:
What is the total number of Post, when Trainer is "Steve Asmussen", and when Time/ Behind is 19 ½?

### Inputs:
table_name: table, columns: ['Finished', 'Time/ Behind', 'Post', 'Horse', 'Jockey', 'Trainer', 'Owner']

### Response:
SELECT COUNT Post FROM table WHERE Trainer = steve asmussen AND Time/ Behind = 19 ½