How do i keep the tail zero in my dataframe and avoid variable lengths differ error from R

Question

I have a dataset like below:-

Location	Reading
Above	0.0370
Above	0.0261
Below	0.0660
Above	0.0420

now when I load this in R, it appears prefectly in the console but when I run the below script-

model <- aov(Reading ~ Belmopan)

it gives

Error in model.frame.default(formula = Reading ~ Belmopan, drop.unused.levels = TRUE) : 
  variable lengths differ (found for 'Belmopan')

when i open the .csv file again, the "0"s were removed.

Can you please tell me what should I do ?

thanks,