Mandarinka a banán

I walked by so fast that I wasn't able to catch what exactly it is, but it seemed to be the name of a Czech painting. Under the Czech name was the English heading The tangerine and a banana. I pondered why the author or translator decided for the definite article in the first case and the indefinite article in the second case. The Czech original doesn't help either, since Czech doesn't have articles. Maybe it's the tangerine because it is the main character portrayed in the painting and it's a banana because it's any banana, like an extra in the plot. Or maybe the author or translator doesn't exactly know how English articles work and decided to use both just in case. I guess I won't have an answer unless I go look at the painting.