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_27547668_3 ( viewers VARCHAR, _number VARCHAR )

### Question ###
How many people watched episode number 13?

### Accurate SQL ###

SELECT viewers FROM table_27547668_3 WHERE _number = 13