Desert zone depends on what kind of seasons you want. Seasons depend on axial tilt (well, that or either an eccentric orbit, but let's assume you don't want to get that exotic, or magical considerations, which I assume you're not including), as does the placement of desert zone(s). An equatorial desert belt goes with a zero or near-zero axial tilt, which also means very mild to non-existent seasons. If that's acceptable to you, then you can keep the deserts where they are. If you want more Earth-like conditions, you'll need an Earth-like axial tilt and this will move the desert into two zones off-set from the equator like the Earth has.