About three dozen of the 365 seats on the District of Columbia's advisory neighborhood commissions remain vacant or undecided following last Tuesday's election, according to unofficial returns.

Numerous tie votes, chiefly the result of write-in balloting, will be decided by the drawing of lots at a future meeting of the Board of Elections and Ethics at which all winners will be officially certified. No date has been set. The board will count absentee and challenged ballots on Friday.

It remains unclear whether those ANC seats for which there were no candidates or winners can legally be filled now that the election is over. If they cannot, the seats will remain vacant until the next election in 1979.

Existing law provides a way for filling vacancies for ANC members who die, resign or move out of the neighborhoods they represented. However, it appears to make no provision for dealing with vacancies created in the event that nobody is elected.

Winfred Mundle, general counsel of the elections board, said he would study the situation and advise the board on steps it might take.

Mundle also said he will consider what to do in cases where they top vote-getter for a seat is not legally qualified to hold the position.

That occurred in at least four instances on the first unofficial list of winners in voting wards one through seven, published Thursday in The Washington Post. All four were the result of write-in votes.

One apparent - but legally disqualified - winner, for ANC district IC8, was Barbara L, Simmons, who was reelected in the same Tuesday election to an at-large seat on the city school board. Shari B. Kharasch, elections board chairperson, said no individual can hold more than one elected post.

Following is a supplemental but still unofficial list of winners of ANC seats in wards one through seven and the list of winners for ward eight, released Friday by the elections board. Seats for which there were no apparent winners (due to lack of candidate or to tie votes) are omitted. Also, omitted are the apparent winners listed on Thursday. Write-in candidates are identified by (w):