Electrolytic Cap in parallel with ceramic for Decoupling
When you have two different capacitors in parallel you might run into problems with antiresonance. This phenomen is discussed more e.g. in here Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values? 

To put it shortly, you'll probably lose some filtering power on some frequencies right below the resonant frequency of the ceramic capacitor. Though, Electrolytic capacitors tend to have high ESR compared to ceramic caps, which reduces the effect of antiresonance.

You can also try to mitigate the problem by adding a small inductor or a ferrite bead between the capacitors, though their inductance might cause different problems depending on what you are doing.

The antiresonance is also not a problem if there isn't anything consuming current or causing noise at the antiresonant frequency. And if there is, you can just change the value of the ceramic capacitor to move the antiresonance to a frequency where it doesn't matter.