Have you seen the bee bringing any leaves to the chair and pushinf bits of leaf into the chair? Or any soil? If so, the bee is just making a little nest where it will lay one egg. When it has laid the egg it will seal up the hole with more leaf, making a little parcel and fly away and you will never see it again. After that, the egg will hatch into a little grub, and after that the grub will become a little bee which will fly away and leave you in peace.
So you have nothing to worry about. The bee is not aggressive and is very unlikely to bother you - it just wants to borrow your chair as a cradle for a few weeks.