Pretty much as the title states.
If a player is under the effect of a potion of speed
When you drink this potion, you gain the Effect of the haste spell for 1 minute (no Concentration required). The potion’s yellow fluid is streaked with black and swirls on its own.
or a Potion of Heroism
For 1 hour after drinking it, you gain 10 Temporary Hit Points that last for 1 hour. For the same Duration, you are under the Effect of the bless spell (no Concentration required). This blue potion bubbles and steams as if boiling.
Do those effects wear off if the play is reduced to 0 hit points and becomes unconscious before the 1 hour duration?