Who makes Douglas Leader toilet?
Douglas is the company that made the toilet. The model is "Leader". I have this exact one in my bathroom that I purchased at a yard sale and I just finished installing it yesterday.
The following was taken, in part, from the FAQs of the Vintage Plumbing website (http://www.vintageplumbing.com):
The John Douglas Co of Cincinnati OH was one of the great 19th and early 20th century American plumbing manufacturing companies, that probably went out of business in the depression, like so many others. It was first established in 1887. The company's trademark was the moon in crescent and the logo "The best is cheapest", and the label markings on a Douglas toilet are among the best ever seen on old antique toilet bowls. Usually the company name is written in large stylized lettering on the back or front rim surface, or the logo is at the back near the seat hinge holes, and the model name is down inside the bowl under the back rim. Some of the Douglas toilet models that were most common were called Gloria, Royal, Favorite, Leader, Excelcius, Yale, Empire, Capitol, and Avon. These bowls date from around 1900 to the mid twenties.