LEADERS AT ODDS ON SPENDING.(MAIN)

Byline: JAMES M. ODATO Capitol bureau

Albany If there is one thing Republican senators, Assembly Democrats and Gov. George Pataki agree on, it's that 1999 will see a slowing New York economy and weaker job growth than in 1998.

However, the three parties disagree on the amount of tax revenue the state will have for spending this coming fiscal year. In fact, the Assembly and Senate are at least $900 million apart.

The numbers surfaced Monday as lawmakers released separate economic forecasts.

The reports are the first steps in the process to create a 1999-2000 legislative budget for Pataki's review.

The forecasts show that Pataki's …