Massachusetts Gov. Michael S. Dukakis and Sen. Paul Simon (D-Ill.) were the winners of a presidential preference poll taken by the union of the nation's postal letter carriers. The two liberal Democrats split just over one-fourth of the responses in the poll of members of the National Association of Letter Carriers.

This is the second poll in recent weeks in which unionized federal workers picked liberal Democrats as their top choice for president, and ranked all Republican candidates at or near the bottom.

In the letter carriers poll, several thousand members of the union participated. The union represents 300,000 current and former postal workers.

Ballots listing then- announced candidates alphabetically were mailed to members in the union's monthly magazine in January, and results were announced during the weekend.

The postal poll differs somewhat from an earlier poll, which drew a smaller response, by the American Federation of Government Employees, a predominantly white-collar union.

In the AFGE poll 28 percent indicated "no preference." Dukakis was the most popular, with 19 percent of the mail ballots returned; Rep. Patricia Schroeder (D-Colo.) and Jesse L. Jackson tied for second with 10 percent, Rep. Richard A. Gephardt (D-Mo.) got 9 percent and Sen. Joseph R. Biden Jr. (D-Del.) got 5 percent. Simon got 4.9 percent in the AFGE poll, as did Vice President Bush and Sen. Albert Gore Jr. (D-Tenn.).

In the letter carriers' poll, two of the top favorites, former senator Gary Hart (D-Colo.) and New York Gov. Mario Cuomo, were write-ins. Cuomo is not an announced candidate and Hart got back in the race after the union had mailed ballots to its members.

Although not on the ballot, Hart was favored by 7.6 percent of the members who responded, with Cuomo getting 7 percent. That put both ahead of all the Republican candidates as well as Democrat Bruce Babbit, the former Arizona governor.

The poll broke down this way:

Dukakis, 13.6 percent; Simon, 13.2 percent; Gephardt, 10.1 percent; Gore, 9.8 percent; Jackson, 8.8 percent; Hart, 7.6 percent; Cuomo, 7 percent; Babbitt, 6.7 percent.

Bush and Sen. Robert J. Dole (R-Kan.) each got 5 percent. Less than 1 percent expressed preference for other candidates.Leave Chart

The Washington Post's 1988 Leave Chart for federal-postal workers is scheduled to run in this space tomorrow. Please clip and save it as reprints will not be available from The Post.

Meeting

Rep. Frank R. Wolf (R-Va.) will talk about merit pay and federal compensation at Friday's luncheon of the Professional Managers Association at the Touchdown Club. Call Dorothy Benson at 523-8521.

Awards

Feb. 29 is the deadline for nominations for the Public Employees Roundtable's public service excellence awards. Nominations may come from individuals, federal agencies or businesses. Winners will be honored at a special breakfast in May on Capitol Hill. For details call 535-4324.