The pot is full of weeds and the saucer is full of water, not good growing conditions for any plant.
The pot is too small and it looks like the tomat has been struggling for some time
If you plant in pots then lose the saucer.
Select a pot that is big enough. If you have a dwarf tomato then a small pot is enough. If you have a determinate you can get away with a five gallon pot if you feed it well. For indeterminates you should have at least a 15 gallon pot or bigger. I like 18 gallon pots. Indeterminates will get 8 ft tall or more so put a trellis in when you plant.
In a pot, choose a good potting soil, not dirt. Add 1/2 to 2 cups of vegetable fertilizer and either mix it in or divide it and give 1/2 cup in the starter mix and give the rest in divided increments monthly over the life of the plant ( 1 tablespoon on the 4th, sixth week and monthly thereafter. I have a tomato fertilizer that is 9-12-12 and it works fine.
Plant your starter tomato deep. Choose a variety suitable for your climate.
Mulch the pot to keep weeds down. Water thoroughly daily, but try to avoid wetting the leaves late in the day. It is best to water in the early morning.
Remove the lower leaves from the plant, they will get disease first.
Treat problems early. Check for pest and pick them off or select a method that takes care of the problem with the least toxicity.
In hot humid weather, you will need to do preventive fungicides.
Birds and pests will go after good fruit, so you will have to bag or net them. They don't go after fruit that does not taste good.
Tomatoes should have 6 hours of good sun, but pots get hot and cook roots on cement. So put the pot on a dirt surface or put the pot inside a larger pot to insulate it from the heat.