[Fixed]-Field 'blah_1' doesn't have a default value when there is no such field

Seems like, there was field blah_1 in your model, but it was not correctly removed from database layer.

You could try to find the commit, where the field was removed (in case, if you are using VCS), probably, it also contains the migration.

You could also try to run ./manage.py makemigrations <your_app_name> in order to create migration, or write it yourself.