"Domicile" is tax terminology for your main, primary home. If your main, primary home is now in Ohio, then Ohio is now your domicile.
On the other hand, if you kept your main home in California and you went to Ohio for some temporary purpose (for example, to attend college), then California would remain your state of domicile.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.