What Duolingo score do you need for Southeastern Louisiana University?

Neither page gives a Duolingo validity period or subscore rule. The graduate page says a student who has studied in the US for one full year in an academic programme does not need to take the TOEFL or IELTS.

For comparison, both pages set IELTS at 6.5 overall, per Southeastern's graduate criteria.

Freshmen can also show college-level English with ACT English 18, SAT ERWS 500 or Accuplacer NG Writing 250. At graduate level, conditional admission cannot be offered to international students on F-1 or J-1 visas.

Requirements vary by programme and change between admissions cycles. The score that binds you is the one on your Southeastern programme page and in your offer letter, so check it there before you book a test.