Among paragraphs with paragraph number between 1900 to 1950, list the texts said by a character described as a sea captain, friend to Sebatian.
paragraph number between 1900 to 1950 refers to ParagraphNum > = 1500 AND ParagraphNum < = 1950; texts refers to PlainText; a character described as a sea captain, friend to Sebatian refers to characters.Description = 'a sea captain, friend to Sebastian'
SELECT T1.description FROM characters AS T1 INNER JOIN paragraphs AS T2 ON T1.id = T2.character_id WHERE T2.PlainText = 'a sea captain, friend to Sebastian' AND T2.ParagraphNum BETWEEN 1500 AND 1950