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_63 (usn_2013 INTEGER, cnn_2011 VARCHAR, bw_2013 VARCHAR, forbes_2011 VARCHAR)

### Question ###
What is the USN 2013 ranking with a BW 2013 ranking less than 1000, a Forbes 2011 ranking larger than 17, and a CNN 2011 ranking less than 13?

### Accurate SQL ###

SELECT SUM(usn_2013) FROM table_name_63 WHERE bw_2013 < 1000 AND forbes_2011 > 17 AND cnn_2011 < 13