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_52 (round INTEGER, pick__number VARCHAR, position VARCHAR)

### Question ###
Which Round is the average one that has a Pick # larger than 26, and a Position of defensive back?

### Accurate SQL ###

SELECT AVG(round) FROM table_name_52 WHERE pick__number > 26 AND position = "defensive back"