Determine the children nodes from a DAG in a SQLite database

I have as input an SQLite database of a directed acyclic graph (not necessarily connected) where the nodes are stored as

node_id | name
1       | a
2       | b
3       | c
4       | d
5       | e
6       | f

and the edges are stored as:

edge_id | source | target
1       | 1      | 2
2       | 1      | 3
3       | 1      | 4
4       | 2      | 5

This is a toy example, my database has about 10^4 to 10^5 nodes (small but not trivially so). I need to query all of the "children" nodes from a given node. As an example:

input | expected output
1     | [2,3,4,5]
2     | [5]
3     | []
6     | []

I am using python's SQLite3 module to do this now, but I have to recursively make a select call for each node -- this can get prohibitively expensive. Is there a smart way to do this, perhaps with a single SQLite call?