In SQL Server, you can use the following query to determine the partitioning column for a partitioned table.

SELECT 
    t.name AS [Table], 
    c.name AS [Partitioning Column],
    TYPE_NAME(c.user_type_id) AS [Column Type],
    ps.name AS [Partition Scheme] 
FROM sys.tables AS t   
JOIN sys.indexes AS i   
    ON t.[object_id] = i.[object_id]   
    AND i.[type] <= 1
JOIN sys.partition_schemes AS ps   
    ON ps.data_space_id = i.data_space_id   
JOIN sys.index_columns AS ic   
    ON ic.[object_id] = i.[object_id]   
    AND ic.index_id = i.index_id   
    AND ic.partition_ordinal >= 1 
JOIN sys.columns AS c   
    ON t.[object_id] = c.[object_id]   
    AND ic.column_id = c.column_id   
WHERE t.name = 'Movies';

Result:

+---------+-----------------------+---------------+-----------------------+
| Table   | Partitioning Column   | Column Type   | Partition Scheme      |
|---------+-----------------------+---------------+-----------------------|
| Movies  | MovieId               | int           | MoviesPartitionScheme |
+---------+-----------------------+---------------+-----------------------+

Be sure to swap Movies with your table name.

In my case the partitioning column is MovieId and its an int type.