If Leon was still that Mage apprentice with only a couple of golems, the "battle" before him might actually be a little more stimulating and exciting.
Sadly...
The number of low-quality golems, like the clay golems, in Leon's storage belt had already hit triple digits. Even intermediate golems like the stone serpents were being summoned in squads. Leon's golem army was already shaping up nicely, with the exception that his collection of pseudo-Mage level golems was still lacking.
The clay golems were extremely tough to deal with when they appeared in such large numbers.
In all honesty, a clay golem with the power of an intermediate apprentice should have a difficult time fighting against a disciplined witcher-knight. The golems made of clay weren't as tough as stone golems or steel golems. The crude magical weapons and knight battle techniques of the witcher-knights could reliably destroy half a clay golem's body with a single strike.