Question tag on "one"

*One should do one's duty, ....................?

I am confused about the above tag question. Because Some use "shouldn't you", some use "shouldn't we" and some use "shouldn't they" for the above tag question. But in my opinion it should be "shouldn't one" as one is an indefinite pronuon. Besides, we know that The subject of the tag question must be pronoun. Here, being "one" pronoun, it seems to me to be "shouldn't one"

Now I need your help for this.