The House Democratic leadership, blindsided by a coalition of Republicans and conservative Democrats, was forced suddenly in mid-debate yesterday to withdraw its first spending resolution of the year.

The embarrassing episode came on a $40.3 million resolution, a 1.7 percent increase over last year's authorized level, to fund House committee staffs for calendar 1982. While the bill involved relatively insignificant amounts, both sides saw the confrontation as foreshadowing battles over larger spending and debt ceiling bills.

Republicans, joined by southern conservative Democrats, contended that the increase amounted to 11 percent in actual spending, which they said was unacceptable at a time when Congress is asking constituents to accept cuts in social services.

Although Frank Annunzio (D-Ill.), chairman of the House Administration Committee, gave an impassioned defense of the resolution as frugal and restrained, Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) decided to pull the bill as it became apparent that Republicans were trying to take political credit for being even stingier than the Democrats.

"Why should we allow the Republicans at the start of the session to say they're for cutting spending when it's a sham battle?" O'Neill told reporters afterward. "We're talking about $4 million . . . . This is playing chicken for some publicity that you're cutting the budget."

Annunzio had thought ranking minority members of the 24 committees would support him. But when Rep. James K. Coyne (R-Pa.) proposed returning the resolution to committee, they jumped ship. The Democrats, realizing they lacked the votes, sent the bill back to the Rules Committee, from which it is expected to return to the floor next week with a new rule allowing amendments that would permit a bipartisan compromise.