As other have said, she files a resident OH return and pays OH income tax on all her income. OH gives her a credit or partial credit for any tax paid to another state (VA) or DC.
The question of whether she needs to file a DC return is not clear, to me. I was under the impression that DC is "reciprocal" with all other states (Reference:https://www.thebalancemoney.com/state-with-reciprocal-agreements-3193329) . As a non-resident, she files form D-4A with her employer to keep them from withholding DC income tax. If DC tax was withheld, she can file a DC return for a refund.
D-4A form: https://otr.cfo.dc.gov/sites/default/files/dc/sites/otr/publication/attachments/2018%20D-4A.pdf
