Problem with enlarging logical partition

After reassigning space to logical volume /dev/educacion-vg/root .

When I see all the partitions the /dev/dm-0 folder that maps to the logical partition /dev/educacion-vg/root shows no changes:

df -h
S.ficheros                     Tamaño Usados  Disp Uso% Montado en
/dev/dm-0 // esta llena                       9,1G   8,5G  127M  99% /
udev                              10M      0   10M   0% /dev
tmpfs                            773M   9,1M  764M   2% /run
tmpfs                            1,9G    11M  1,9G   1% /dev/shm
tmpfs                            5,0M   4,0K  5,0M   1% /run/lock
tmpfs                            1,9G      0  1,9G   0% /sys/fs/cgroup
/dev/sda1                        236M    49M  175M  22% /boot
/dev/mapper/educacion--vg-home   896G   8,1G  843G   1% /home
tmpfs                            387M   4,0K  387M   1% /run/user/116
tmpfs                            387M   8,0K  387M   1% /run/user/1000

But if I do a lvdisplay you can see the change:

lvdisplay
  --- Logical volume ---
  LV Path                /dev/educacion-vg/root
  LV Name                root
  VG Name                educacion-vg
  LV UUID                3RZSQ8-xxLm-3Dqv-RaU0-vrAP-gnEG-sR4w5s
  LV Write Access        read/write
  LV Creation host, time educacion, 2016-12-05 17:27:06 -0300
  LV Status              available
  # open                 1
  LV Size                13,47 GiB
  Current LE             3448
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:0

I do not know what is happening. Thank you.