If there were longer days and longer nights, would we stay awake for longer and sleep for longer to adapt to the sunlight?

That's what happens to spelunkers, cave explorers and other people who's relationship with the sun changes like astronauts. In caves with zero sunlight, the pineal gland can't react to sunlight; turning on and off with the sun, which is why some people can't sleep if any light gets in the room. So other sleep systems such as adenosine as the end product of muscle use take over which does result in increasingly extended sleep and wake cycles.

I don't know what the record is but I don't think many people want to spend too long down there to find out.

Maybe. But millennia of evolution has your body on a 24 hour cycle. You MIGHT adapt but it would likely come with some long term health issues.

Your body would determine your sleep needs it wouldnt matter if it is light or dark outside.

I work 12 hrs a day and up about 15 hours...it doesnt matter the time of day because im tired.

Stay up for 20 hours..

That's doubtful, which is a polite way of saying, no.  All the evidence suggests that that would not happen.  People who live near the poles don't sleep for most of the winter and stay awake for most of the summer despite the sun not going over the horizon at mid-winter and not setting at midsummer.  We're not even set for the current length of day but the speed the earth used to turn at millions of years ago, so without the cues of day and night people drift from a regular sleeping pattern.  Plus, we naturally don't sleep in a single stretch.  That something we've been culturally conditioned to do.  In primitive cultures people slept in two stretches with a waking period in the middle.  We did that in the west too until lighting became cheap enough to use more generously at night and people's sleeping habits started to change by going to bed later and sleeping through until the old wake up time of the second sleep.  When submariners have been under the sea for a long time they naturally revert to two-part sleeping in accordance with the old, shorter spin of the earth around the time we emerged from the primordial ooze.

Probably 'days would just be shorter say 12 hour day, 12 hour nights, etc. The human body cannot normally operate 20 hours at a time over a long period.