Copy table values to another table with + column

Hy I have to tables A and B I need to copy from A the values in B. I wrtied an sql like this:

insert into B (UPDATE_FILE, RUN_DATE, CREATED_DATE) 
SELECT UPDATE_FILE, RUN_DATE from A 

my problem is cause table A did not have created_date column. And in B the created_date is not null. How can I set a default value to created_date or the current time with this sql? I am using SQLiteStudio 3.0.6