There is no "Settings - Account" section is the latest iOS version and therefore I assume you meant the Accounts section under Settings - Mail, Contacts, Calendars. Anyway, initiate the native Calendar app and then select "Calendars" at the bottom of the screen. Afterwards, make sure there is a checkmark next to each calendar that's listed or uncheck all of them except the calendar you're referring to. If you want it to be your default calendar, go to the aforementioned settings, scroll down to "Calendars" section and then make the necessary changes in the "Default Calendar" section.