If you have multiple objects for each level and want to choose a random object from that level selection, then I would have a family per level and use code along the lines of:
If level = 1 | Spawner spawn family1
If level = 2 | Spawner spawn family2
Spawning from a family automatically chooses a random object.
If however you want to spawn a specific object, then the family doesn't help you so much and you're better off using:
If level = 1 | Spawner spawn object1
If level = 2 | Spawner spawn object2
In Construct 3 you can spawn objects by name, which allows you to reduce the total number of events but in C2 you have to call object spawns in separate conditions or use a 3rd party plugin.