Update duckdb index files

.gitattributes

@@ -2,3 +2,4 @@ nbroad--small_arxiv_classification/parquet-train.parquet filter=lfs diff=lfs mer
 nbroad--small_arxiv_classification/parquet-test.parquet filter=lfs diff=lfs merge=lfs -text
 nbroad--small_arxiv_classification/parquet-validation.parquet filter=lfs diff=lfs merge=lfs -text
 nbroad--small_arxiv_classification/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+nbroad--small_arxiv_classification/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

nbroad--small_arxiv_classification/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:afafaf83b249324b5ae7cb48072b90896cc712f111c3b64c68ccb634651133e1
+size 49819648