Your question is actually slightly complicated as the SSHD's normal HDD components run slower, but it does have some SSD memory.
1) The small amount of SSD memory will be allocated primarily to booting Windows faster and launching other files/programs faster (based on usage pattern).
2) Games on a good SSD will launch faster, but it's not a huge amount. It averages about 2x as fast but this varies depending on videos you can't skip etc. It's rarely 3x faster.
3) Once a game launches, the SSD rarely matters except for loading times (handy for games like SKYRIM though for jumping around the map or entering buildings).
For League of Legends I wouldn't expect much difference.
4) SSHD vs SSD:
The problem with GAMING however is two-fold:
a) There isn't much SSD memory in an SSHD so it's difficult to say how much difference it makes for a game, especially if you have several games. Skyrim for example, is a larger game than all of the SSD memory on an SSHD so chances are it won't make much difference much of the time to jump around the map.
b) The HDD component of the SSHD is actually SLOWER than your 7200RPM drive. So anytime the data isn't cached to the SSD memory in the SSHD it will actually be running slower from the 2.5" SSHD's mechanical platters.
This depends on how much you want to BUDGET. I've recommended the following to others:
1) 120GB SSD for main drive (can clone from HDD)
2) 1TB+ HDD for games, storage, backups etc
3) 120GB+ SSD for games that benefit from an SSD (a third drive)
*So I have Windows and apps on a Samsung EVO SSD, Steam and everything else on a large HDD, and another SSD dedicated solely to games like Skyrim that benefit from an SSD. For STEAM, you can even designate a 2nd folder to easily move your games (backup, delete local content, then restore game to 2nd steam folder)