Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_40 (duration VARCHAR, spacecraft VARCHAR)

### Question ###
What is the duration of the Expedition 20 ISS Zvezda?

### Accurate SQL ###

SELECT duration FROM table_name_40 WHERE spacecraft = "expedition 20 iss zvezda"