How to query for err in MySQL?

I added a column to my table that does not allow null. I guess that is why some of my rows now have real values in the column but some other rows now have (err) in the column. How can I query for this?

select * from Table where new_column = err

That doesn't work.

select * from Table where new_column='err'

select * from Table where new_column is null I think this will work, but my MySQL skills are rusty