01/02 WASHINGTON (AP) -- The 103rd Congress convenes Tuesday, infused with newcomers and eager to prove it heard voters' demands to end years of partisan stalemate once President-elect Clinton takes office. But Congress and the new president will face formidable problems: reform of the nation's health care system, stimulus for the economy, reining in the deficit and an array of social issues. "There are obviously going to be differences of opinion, and I expect that Republicans, as is their right, will oppose some of his initiatives," Senate Majority Leader George Mitchell of Maine said in a telephone interview last week. "But I'm hopeful that on the important issues of economic growth and dealing with the deficit, health care reform, and others, that we'll be able to get action this Congress." At the same time, Clinton will be confronted with his own campaign promises, such as a tax break for the middle class. And he will have to decide whether a line-item veto to control spending is worth the battle it will take to overcome strong Senate opposition. Clinton has promised to send Congress his health-care reform plans within 100 days. Although there is wide agreement something must be done about a system that costs over $800 billion a year yet leaves 35 million people without coverage, consensus on what to do remains elusive. Mitchell said he, Clinton and House Majority Leader Richard Gephardt have agreed to work together to try to come up with a health care plan capable of wide support. Mitchell and Gephardt tried without success to forge a health consensus last year. To buy time on that and other big issues, congressional leaders plan early action on some other bills that were frustrated by President Bush's opposition or veto over the past four years. House Speaker Thomas Foley, D-Wash., said the House would act on new versions of the family and medical leave, easier voter registration, and campaign finance reform -- probably in that order. The House and Senate meet at noon Tuesday to swear in new members and conduct other formalities. Senate committees will begin considering Clinton's Cabinet selections right away, starting with Commerce-secretary designate Ron Brown on Wednesday. The new Congress will meet for only a couple of days, however, before recessing to await the new president's inauguration on Jan. 20 and the arrival of the first Democratic administration in a dozen years. The new Congress will be vastly different from the previous one, which was beset by scandal and embarrassment. There are 110 freshmen in the new House, one-quarter of its membership. The Senate will have six women, including its first black female, Carol Moseley Braun of Illinois. Blacks, Hispanics and women all have increased numbers. Republicans gained slightly in the House but remain heavily outnumbered by Democrats; the Senate retains its 57-43 Democratic majority.