let's say that in a dungeon at level 1 you find draugrs, at level 30 you find draugr wraiths, at level 50 you find draugr deathlords
But not in the same dungeon. Within any particular dungeon, enemies are fixed by your level the first time you enter. Thus if you so (say) Bleak Falls Barrow at level 5, then it will always be low-level enemies, even if you go in again at level 70. But each time you enter a NEW dungeon, it scales to your current level, so ones you enter the first time at level 50 will have top-level enemies; draugr death overlords etc.