Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| School | Location | Mascot | County | Year Joined | Previous Conference | Year Left | Conference Joined |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Hammond Clark | Hammond | Pioneers | 45 Lake | 1969.0 | Northwestern | 2007.0 | Great Lakes |
| Hammond Gavit | Hammond | Gladiators | 45 Lake | 1969.0 | Northwestern | 2007.0 | Great Lakes |
| Hammond | Hammond | Wildcats | 45 Lake | 1969.0 | Northwestern | 2007.0 | Great Lakes |
| Hammond Morton | Hammond | Governors | 45 Lake | 1969.0 | Northwestern | 2007.0 | Great Lakes |
| East Chicago Roosevelt | East Chicago | Roughriders | 45 Lake | 1969.0 | Northwestern | 1986.0 | none (consolidated into East Chicago Central ) |
| Hammond Tech | Hammond | Tigers | 45 Lake | 1969.0 | Northwestern | 1981.0 | none (school closed) |
| East Chicago Washington | East Chicago | Senators | 45 Lake | 1969.0 | Northwestern | 1986.0 | none (consolidated into East Chicago Central ) |
| Whiting | Whiting | Oilers | 45 Lake | 1969.0 | Northwestern | 2007.0 | Greater South Shore |
| Hammond Bishop Noll | Hammond | Warriors | 45 Lake | 1973.0 | Independents | 2007.0 | Greater South Shore |
| East Chicago Central | East Chicago | Cardinals | 45 Lake | 1986.0 | none (new school) | 1987.0 | Independents |
| Calumet | Calumet Township | Warriors | 45 Lake | 1993.0 | Lake Suburban | 2007.0 | Greater South Shore |
| Griffith | Griffith | Panthers | 45 Lake | 1993.0 | Lake Suburban | 2007.0 | Northwest Crossroads |
| Highland | Highland | Trojans | 45 Lake | 1993.0 | Lake Suburban | 2007.0 | Northwest Crossroads |
| Munster | Munster | Mustangs | 45 Lake | 1993.0 | Lake Suburban | 2007.0 | Northwest Crossroads |
| Andrean | Merrillville | Fighting '59ers | 45 Lake | 1998.0 | Independents | 2007.0 | Northwest Crossroads |
| Lake Station Edison | Lake Station | Fighting Eagles | 45 Lake | 1998.0 | Northwest Hoosier | 2007.0 | Greater South Shore |
| Lowell | Lowell | Red Devils | 45 Lake | 1998.0 | Northwest Hoosier | 2007.0 | Northwest Crossroads |
| Hobart | Hobart | Brickies | 45 Lake | 2003.0 | Duneland | 2007.0 | Northwest Crossroads |
| Kankakee Valley | Wheatfield | Kougars | 37 Jasper | 2003.0 | Independents | 2007.0 | Northwest Crossroads |
| Wheeler | Union Township | Bearcats | 64 Porter | 2003.0 | Porter County | 2007.0 | Greater South Shore |
Question:
Which Conference Joined has a Previous Conference of northwestern, and a Mascot of oilers?
Answer:
Greater South Shore