If you look on the 1850 and 1860 Censuses of Avoyelles Parish (and maybe others) many people have the desgination (1) next to their name. I noticed that although there is a column for race in these censuses it is blank. I called ancestry.com and they have no record of this designation being used at all. She said it could very well be a desgination for mulatto, quadroon, octoroon or just generically "creole" meaning any of the above. If the census taker saw the person and thought they were possibly multiracial they could have possibly used this desgination. The ancestry.com person thought it was very interesting and could possibly be confirmed by looking at the Slave Schedules for mulatto children.