Adding other field for multiple categories

I created a dropdown field having "OTHER" field as option and on selecting that a text field should appear.The fields other than "OTHER" have categories.
So,currently that "OTHER" field is not appearing if I leave category of it as blank.It appears only when a single category is passed and passing comma separated multiple categories did not work too.
I want to show it for all categories.

The columns are list_name,name,label,category
How to show "OTHER" field for all categries?