You can use the escape sequence \040 to escape spaces:
# UNCONFIGURED FSTAB FOR BASE SYSTEM
/host/ubuntu/disks/swap.disk none swap sw 0 0
LABEL=Expansion\040Drive /media/Expansion\040Drive ntfs-3g defaults,umask=0022,fmask=0133 0 0
LABEL=Expansion\040Drive_ /media/Expansion\040Drive_ ntfs-3g defaults,umask=0022,fmask=0133 0 0
BTW, you cannot quote part of the string like you mentioned in the question. If you’re quoting, you need to quote the entire string.
Another thing I happen to notice from the output of blkid is that there are 2 partitions (on 2 separate drives sdc1 and sdd1) both having the same LABEL Expansion Drive. To workaround this, you can use UUID instead.
UUID=C682A8EE82A8E3E1 /media/Expansion\040Drive ntfs-3g defaults,umask=0022,fmask=0133 0 0
UUID=D006D78406D769CC /media/Expansion\040Drive_ ntfs-3g defaults,umask=0022,fmask=0133 0 0