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_99 ( pick__number INTEGER, overall VARCHAR, position VARCHAR )

### Question ###
What is the highest pick number of a defensive back with less than 136 overall points?

### Accurate SQL ###

SELECT MAX(pick__number) FROM table_name_99 WHERE overall < 136 AND position = "defensive back"