D.C. Code § 47-1808.06
Individuals carrying on any trade or business in partnership in the District, other than an unincorporated business, shall be liable for income tax only in their individual capacities. The tax on all such income shall be assessed against the individual partners under §§ 47-1806.01 to 47-1806.06. There shall be included in computing the net income of each partner his distributive share, whether distributed or not, of the net income of the partnership for the taxable year; or if his net income for such taxable year is computed upon the basis of a period different from that upon the basis of which the net income of the partnership is computed, then his distributive share of the net income of the partnership for any accounting period of the partnership ending within the taxable year upon the basis of which the partner's net income is computed. The term "accounting period" as used in this section refers to the calendar or fiscal year of a partnership.
D.C. Code § 47-1808.06