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_21350934_2 ( opponent VARCHAR, attendance VARCHAR )

### Question ###
Who is the opponent when the attendance is n/a?

### Accurate SQL ###

SELECT opponent FROM table_21350934_2 WHERE attendance = "N/A"