The first o is the letter omicron itself, not an article. Actually all Greek letters are neuter, not masculine, as you'll see in the phrase 'the bad kappa' here in Duolingo. It's 'το κακό κάππα', using the neuter definite article.
The first bit is intended to be the letter itself, i.e. like "κ κάππα" or "τ ταυ", not a word (the gender marker).
But you're right; it's confusing.
Why does/did the Greek language need two letters for one sound. Why one of them is named "o little" and the second "o big"?
That's a bit like asking why English has the letter "c" when we also have "s" and "k" - because English didn't invent the alphabet but took what the Romans gave them.
The Greeks based their alphabet on that of the Phoenecians, I believe, and so it does not fit the language perfectly.
Also, in Ancient Greek, omicron was a short sound (and a close sound) while omega was a long sound (and a more open one) -- so there the distinction made a lot of sense. Similarly with epsilon (short, close) versus eta (long, open). But alpha, iota, upsilon which could also be long and short do not have separate letters for the two quantities.
Later, the sounds changed and now omicron and omega sound the same... but Greek spelling is partly historical/etymological and so they still use both letters.
Perfect! I'd add that micron means little and mega means big, so omicron/omega mean little and big o...
There are 5 ways of making the /i/ sound in greek, 2 for /e/. And no long sound like /I/ and /i:/
There are 6 ways of making the /i/ sound in Greek, though only 5 of those are common: ι, η, υ, ει, οι.
The 6th is υι, which occurs in a handful of words such as άρπυια (harpy) and υιοθετώ (adopt).
Where the instructions say, "Write this in English" that was a mistake. What it really meant and should have said is "Write this in English letters but do not translate into English." That was not a good instruction.
I thought it was asking for the english translation which would be The o. Is that not right?
It is not right.
Letters of the alphabet are neuter, so "the omicron" would be το όμικρον.
The problem is, no good translator would actually do a completely direct comparison as the languages are different. English does not use "o" in front of words the same way Greek does.
So "Ο όμικρον" translated into English is "The o." or "The omikron". "O omicron" makes absolutely no sense to English speakers. That is why there is a lot of confusion.
Maybe change the prompt to "English transcription" instead of translation?
"translate this sentence" it said, and i did. To English. Got it wrong. This needs to be more specific!