What Duolingo score do you need for the University of Dayton?

Neither page states a Duolingo validity period, subscores or sending instructions, and neither mentions teaching assistantships. The graduate page exempts applicants with a bachelor's degree or higher from a regionally accredited US institution or from listed English-speaking countries.

For comparison, the same pages set IELTS at 6.0 for undergraduate full admission and 6.5 for graduate full admission.

The undergraduate catalog says applicants who cannot meet the English requirement at the time of application may be considered for conditional admission. They attend the Intensive English Program and must complete it or reach the minimum score for their level before full admission. If you apply for conditional admission to an academic programme, you do not need a separate Intensive English Program application.

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