@Leen1 --
The fact that you lived in and maintained your own rented apartment in DC for an entire year would make you a resident of DC for tax purposes. You thus have a situation of dual residency, since NY appears to be your domiciliary state (your primary, permanent residence to which you intend to return). Thus I agree with @DMarkM1 that you are a domiciliary resident of NY and a statutory resident of DC.
Here are NY's rules regarding an "other state credit":
https://www.tax.ny.gov/pit/credits/resident_credit.htm
Page 15 of the DC tax instruction booklet states: "If you are a statutory resident, the state in which you are
domiciled gives you a credit for the taxes paid to DC."
https://otr.cfo.dc.gov/sites/default/files/dc/sites/otr/publication/attachments/52926_D-40_12.21.21_...
Thus you would claim an "other state credit" on your NY return, but not on your DC return.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
