It was difficult to tell the pros from the cons at the fifth and final meeting of a Pennsylvania legislative committee that took testimony here yesterday on the proposed constitutional amendment that would give the District of Columbia full voting representation in Congress.

"We're talking about democracy, a simple concept," began Jeff Drey, speaking for the conservative Philadelphia Caucus. Drey said that "while I agree with the principle, he said he oppossed ratification of the proposal because the District of Columbia "Simply is not a state."

Another witness, state Rep. Joseph A. Lashinger (R-Montgomery County), told the House Committee on State Federal Relations that "I'm deeply committed to the idea of offering the citizens of the District of Columbia full representation in Congress." But then he added that "I feel that this current proposed amendment is not the proper vehicle."

Of 16 persons who testified at the hearing at the University of Pennsylvania Mussum, 10 favored ratification without strings attached. Most of the six opponents also said they favored the idea, but not the method approved by Congress earlier this year. Instead, they suggested statehood for the city or retrocession to Maryland.

A proponent, Prof. Paul Bender, of the University of Pennsylvania Law School, Speaking on behalf of the American Civil Liberities Union, said "the choice is simply do you want it (to give D.C. residents representation) or do you not?"

State Rep. Hardy Williams (D-Philadelphia), one of 10 legislators who outnumbered spectators in the cavernous auditorium of one of the world's great museum's of archeology and anthropology, said he was "disturbed by testimony that the District of Columbia should have representation but . . ."

Williams accused opponents of suggesting such alternatives as statehood or retrocession that they then would oppose on other grounds.

"The bottom line,"said Williams, "is should they have representation?"

Two of the strongest advocates of ratification were former D.C. residents, state ReP. Mark B. Cohen (D-Philadelphia) and Stephen D. Horton, a settlement house worker here.

HOrton said that he had "experienced a personal frustration of not being allowed to vote . . . It's more than taxation without representation. It's moral issue."

Cohen said that "I deeply regret Republican fears that blacks always vote Democratic." He said that while District of Columbia voters "may not be Howard Jarvis clones," if the Republican Party rises to the challenge, "Edward Brooke need not be the only black Republican in the Senate."

Two Republican candidates for the Pennsylvania legislature urged present GOP members of the House to vote fot ratification. George Baxter of Reading warned that history has demonstrated that "those who are bound by tradition will suffer attrition." Sid Bastas of Philadelphia added that "the District is justly called America's last colony."

Prof. Bender, a constitutional lawyer, said the proposed amendment is an "elegantly simple" solution to a complex problem. After listening to opponents, Bender said that "it's hard to imagine any wording that wouldn't lead to objections."

State Rep. James P. Ritter (D-Allentown), the committee chairman, scheduled hearings in Clation, Johnstown, Scranton, Harisburg and Philadelphia after the Pennsylvania House postphoned a vote on ratification last month.