Want LED to stay on once it is triggered
If you feed the output of the comparator back to its input, that will essentially become your "latch" and you won't need a separate FF.  Once the comparator output goes high, it stays on.  Something like this:



The two diodes serve as an OR.  Because of the diode following the output of the op-amp, the voltage will be 0.7v lower, but you can compensate for that either using a different pot, or you can increase the gain of the op-amp slightly.

The diodes can be any general purpose such as ubiquitous 1N4148.