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_15280 ( "Round" real, "Pick #" real, "Overall" real, "Name" text, "Position" text, "College" text )

### Question ###
Position of defensive back, and an Overall smaller than 69 is what lowest pick #?

### Accurate SQL ###

SELECT MIN("Pick #") FROM table_15280 WHERE "Position" = 'defensive back' AND "Overall" < '69'