This is an old one, but a goody. https://www.nps.gov/museum/publications/conserveogram/07-07.pdf

Most of that damage is to the finish. As long as the wood is completely dry, sand the finish to remove the damaged areas and apply stain(if sanded away) and finish. Lightly sand each leg so you can apply finish to the entire leg(s). You could use an exterior varnish.

Before I did anything drastic, I'd try these. As a professional, I've had lots of success with them. Also sold in yellow and black pack as Jasco brand.

Perhaps try either of the following.

Method #1

• Form a paste with equal parts water and baking soda.
• Rub the paste onto the affected area in circular motions until the stain is removed.
• Wipe the surface clean and dry after.

Method #2

• Apply petroleum jelly and let it sit overnight, wiping it off the next day.

If there's any other forms of damage or you wish to simply read from the source, this blog is where I obtained the information from. It covers wooden furniture maintenance.

After you fix the stain, I would suggest adding some appropriate feet to keep the wood from contacting the floor directly.