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

### Instruction:
What is the duration of the Expedition 20 ISS Zvezda?

### Inputs:
table_name: table, columns: ['Start Date/Time', 'Duration', 'End Time', 'Spacecraft', 'Crew']

### Response:
SELECT Duration FROM table WHERE Spacecraft = expedition 20 iss zvezda