The correct verb to use here is "is", however, the form you've given isn't the correct tense - it should be something like "was", "is being", or "will be", depending on when the work occurs.
If the work is completed (which I suspect you want, since you're comparing it to "has"), you would use the past tense, "was done by me".
(other types of past tense would be acceptable, such as "has been done by me" - but note that the main verb is still "is", inflected as "been"!)
If the work is ongoing, you could use the present progressive, "is being done by me".
If you're talking about future work, you would use the future tense, "will be done by me".
In the simple present tense, as you've given, it sounds unnatural in this sentence - a little bit like you're stating a simple teamwork decision as a profound mathematical fact. There are cases where you might do this, but it would require a larger context to sound natural.