Not in the areas you suggested but the Windsor in Shirlington is awesome short term -super flexible, enclosed parking spot, dog park and tons of restaurants right there. Great dog park and bike trails are right across the street, plus bus station and 395 for quick commute.

Try the Upstairs or Whitney in Bethesda

Starting in September, pet friendly, three month lease or sublet of apartment, condo, or house. Bethesda, Chevy Chase, NW DC ok. No more than 2600 a month