Because DC, MD & VA have a reciprocal agreement, you only pay tax on the money you made in these states in your Resident State, DC.
From your question, it sounds like your Employers only withheld DC taxes, so you will only need to file a DC Tax Return this year. The only reason you would need to file VA or MD Tax Returns is if one of your Employers withheld taxes from those States in error. When that situation occurs, you just file a return with VA or MD just to get your withholding refunded.
Because DC, MD & VA have a reciprocal agreement, you only pay tax on the money you made in these states in your Resident State, DC.
From your question, it sounds like your Employers only withheld DC taxes, so you will only need to file a DC Tax Return this year. The only reason you would need to file VA or MD Tax Returns is if one of your Employers withheld taxes from those States in error. When that situation occurs, you just file a return with VA or MD just to get your withholding refunded.