Table:
0
A
B
C
D
E
1
District
Vacator
Reason for change
Successor
Date successor seated
2
Connecticut At-large
Uriel Holmes (F)
Resigned sometime in 1818
Sylvester Gilbert (DR)
Seated November 16, 1818
3
North Carolina 11th
Daniel Forney (DR)
Resigned sometime in 1818
William Davidson (F)
Seated December 2, 1818
4
Massachusetts 20th
Albion K. Parris (DR
Resigned February 3, 1818
Enoch Lincoln (DR)
Seated November 4, 1818
5
Virginia 19th
Peterson Goodwyn (DR)
Died February 21, 1818
John Pegram (DR)
Seated April 21, 1818
6
Louisiana At-large
Thomas B. Robertson (DR)
Resigned April 20, 1818
Thomas Butler (DR)
Seated November 16, 1818
7
Pennsylvania 4th
Jacob Spangler (DR)
Resigned April 20, 1818
Jacob Hostetter (DR)
Seated November 16, 1818
8
Pennsylvania 6th
Samuel D. Ingham (DR)
Resigned July 6, 1818
Samuel Moore (DR)
Seated October 13, 1818

Questions and formulas:
Question: The successor for the Massachusetts 20th district was seated on what date?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,A1="Massachusetts 20th"),5))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E8,A2:A8="Massachusetts 20th"),5))
Level: medium
Question: Who vacated the Pennsylvania 6th district?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,A1="Pennsylvania 6th"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E8,A2:A8="Pennsylvania 6th"),2))
Level: medium