A post-Iowa Democratic debate poll, conducted over the weekend by KRC Research for WBZ-TV Boston, offers clues that the Iowa campaign of Rep. Richard A. Gephardt (D-Mo.) may be picking up. The poll of 403 likely caucus attendees puts Gephardt at 19 percent, Gary Hart 16 percent, Sen. Paul Simon (D-Ill.) 15 percent, Massachusetts Gov. Michael S. Dukakis 13 percent, Jackson 6 percent, former Arizona governor Bruce Babbitt 5 percent, Sen. Albert Gore Jr. (D-Tenn.) 2 percent and 22 percent undecided.

The plus-or-minus 5 percent margin of error may mean the double-digit four are essentially tied, but other poll indicators hint that Gephardt's populist message and paid media campaign may be catching on. When asked if they had seen television ads for any candidate that would make them more likely to vote for that candidate, 22 percent cited the Gephardt ads, 7 percent Simon's ads and 5 percent Dukakis' ads.

Gephardt has been on the air with commercials since Dec. 26 and Simon has been running television ads for the last two weeks. The Dukakis campaign aired ads only for the week of Jan. 4-10, but went back on the air yesterday.