In RPG MAKER 2000/2003 there are two ways to this that I know of.
The first way is to make the battle and victory music the same music as the level music therefore the music will never change.
The second way is pretty messy and has its problems. You make your battle music a wave file so it can be considered a sound effect. For every monster group you have, in their battle events tab make it so it plays the battle music sound effect file and make it play the level music but change the volume to zero. Then make it turn on a switch called something like After Battle and turn off a switch called something like Before Battle. (This battle event will be activated by having the switch Before Battle On). Then when you exit the battle have a auto activate switch in the level that only works if the After Battle switch is on. Have this auto event turn off the battle music sound effect file, play the level music at full volume, turn on the Before Battle switch and turn off the After Battle Switch.
NOTE: With this method, you can not have victory music and sometimes the battle sounds effects screw with the battle music sound effect and turn it off. Also the level music does not stop playing. For instance if you are in the level and before you get into the battle u walk around for 20 seconds so 20 seconds of the level music went by. Lets say the battle took 30 seconds. When you get out of battle the level music will start playing at 50 seconds and not 20 seconds because it was playing in silence during the battle
Discord
Light Style