10. They will say, "Our Lord, remove from us the torment; indeed, we are believers."[44:12]

 رَّبَّنَا ٱكْشِفْ عَنَّا ٱلْعَذَابَ إِنَّا مُؤْمِنُونَ

Who are they? Will their supplication answered?

السلام عليكم ورحمة الله وبركاتة      

ﺑِﺴْـــــــﻢِﷲِﺍﻟﺮَّﺣْﻤَﻦِﺍلرَّﺣِﻴﻢ

Answer:

The disbelievers make this supplication, when they experiances punishment in this world or in the Hell, they will ask for it to be taken away from them. But it will be denied by Allah.

Explanation:

Several ayaath in the Quran have warned the disbelievers similarly:

(14:44) And warn mankind of the Day when the torment will come unto them; then the wrongdoers will say: “Our Lord! Respite us for a little while, we will answer Your Call and follow the Messengers!” (It will be said): “Had you not sworn aforetime that you would not leave (the world for the Hereafter)".

(34:51-52) And if you could but see, when they will be terrified with no escape, and they will be seized from a near place. And they will say (in the Hereafter): “We do believe (now);” but how could they receive (faith and its acceptance by Allah) from a place so far off…

(6:27) "If you could but see when they will be held over the (Hell) Fire! They will ask: “Would that we were but sent back (to the world)! Then we would not deny the Ayat of our Lord, and we would be of the believers!” 

Allah (Ajj wa jall) says even when they were returned to the world they behave in the same manner:

[6:28] But if they were returned (to the world), they would certainly revert to that which they were forbidden. And indeed they are liars.

Indeed, We will remove the torment for a little. Indeed, you [disbelievers] will return [to disbelief] [44:15]

On that Day will man remember, but how will that remembrance (then) avail him (89:23)

And though We had mercy on them and removed the distress which is on them, still they would obstinately persist in their transgression, wandering blindly.(23:75)

[44:13 and 14] How can there be for them an admonition, when a Messenger explaining things clearly has already come to them. Then they had turned away from him and said: “He is a madman!”

Allah, the Great  and Merciful had sent them a Messenger with a clear Message and warning. Yet despite that, they turned away from him, opposed him and rejected him.They were the great losers.

The same thing happened during Prophet's time. When the stubborn Quraysh  denied the truth of Islam and the Messenger of Allah [SAW] invoked Allah against them the drought and famine like that of Yusuf (AS)'s time. They became so hungry and tired that they never spared bones and dead meat as their food. 

A man came to the Messenger of Allah [SAW] and said, “O Messenger of Allah! Pray to Allah to send rain to Mudar, for they are dying. So the Prophet (SAW) prayed for rain for them, and they got rain. Then the Ayah was revealed: "Verily, We shall remove the torment for a while. Verily, you will revert."

الحمدلله