Should I add it as an additional column or a seperate table?
from your question i understand that you have a "One to many" relationship between The Division to the Regions,

the best way with this kind of relational data from my experience is to create a Division table and a Region table that holds the DivisionID.

that will also use less storage space because you won't need to write the division name in string, you can reference the int ID column value that uses less space than the string(char/varchar etc.)
:)
example

    CREATE TABLE  dbo.Division
(
    [ID] [int] NOT NULL IDENTITY(1,1) CONSTRAINT PK_Division PRIMARY KEY,
    [Name]  NVARCHAR(255) NOT NULL
)

CREATE TABLE  dbo.Region 
(
    [ID] [int] NOT NULL IDENTITY(1,1) CONSTRAINT PK_Region PRIMARY KEY,
    [Name]  NVARCHAR(255) NOT NULL,
    DivisionID INT CONSTRAINT FK_DivisionRegion FOREIGN KEY REFERENCES dbo.Division (ID)
)


shimon.